If you have an underlying heart condition, avoid polluted air in the Delhi-NCR region as researchers now report that higher exposure to PM 2.5 and PM 10 in such patients can worsen their condition, including a heart attack.

In a paper published in the Journal of the American College of Cardiology, a team of global researchers aimed to evaluate the association between long-term exposure to particulate matter 2.5 (PM2.5) and 10 (PM10), and coronary vasomotor disorders in non-obstructive coronary artery disease (NOCAD) patients.

Coronary vasomotor abnormalities are important causes of myocardial ischemia in patients with NOCAD. However, the role of air pollution in determining coronary vasomotor disorders has never been investigated.

The team studied patients with myocardial ischemia and NOCAD undergoing coronary angiography and intracoronary provocation test.

Nearly 287 patients with chronic myocardial ischemia and nonobstructive coronary arteries and myocardial infarction with nonobstructive coronary arteries (MINOCA) were enrolled in the study.

They found that higher exposure to PM2.5 and PM10 in patients with myocardial ischemia and NOCAD is associated with coronary vasomotor abnormalities.

"In particular, PM2.5 is an independent risk factor for the occurrence of epicardial spasm and MINOCA as clinical presentation," they wrote.

Ultimately, reduction in air pollution levels is the logical treatment for air pollution-induced vascular dysfunction and cardiovascular disease.

In April this year, a study claimed that exposure to air pollutants -- even at levels below World Health Organisation (WHO) air quality guidelines -- may trigger a heart attack within an hour.

The study found exposure to any level of four common air pollutants -- fine particulate matter, nitrogen dioxide, sulphur dioxide and carbon monoxide -- could quickly trigger the onset of acute coronary syndrome (ACS).

ACS is an umbrella term describing any situation in which blood supplied to the heart muscle is blocked, such as in a heart attack or unstable angina, chest pain caused by blood clots that temporarily block an artery.

The study was published in the American Heart Association's journal Circulation. (SJ/IANS)